Configuring EoA Interfaces

Topics on this page: Viewing Your EoA Setup | Adding EoA Interfaces

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This topic describes how to configure an Ethernet-over-ATM (EoA) interface on the ADSL/Ethernet router, if one is needed to communicate with your ISP. This interface is also commonly referred to as an RFC1483 interface, for the name of the Internet specification to which it conforms.

The Ethernet-over-ATM (EoA) protocol is commonly used to carry data between local area networks that use the Ethernet protocol and wide-area networks that use the ATM protocol. Many telecommunications industry networks use the ATM protocol. ISPs who provide ADSL services often use the EoA protocol for data transfer with their customers' ADSL modems.

EoA can be implemented to provide a bridged connection between a ADSL modem and the ISP. In a bridged connection, data is shared between the ISP's network and their customer's as if the networks were on the same physical LAN. Bridged connections do not use the IP protocol. EoA can also be configured to provide a routed connection with the ISP, which uses the IP protocol to exchange data.

Before creating an EoA interface or modifying the default settings, contact your ISP to determine which type of protocol they use.

PPP vs. EoA: Your ISP may use a protocol other than EoA for communication with your ADSL X4, such as the point-to-point protocol (PPP). One type of PPP, named PPP over Ethernet (PPPoE), actually works "on top" of the EoA protocol. The other type, PPP over ATM (PPPoA), does not. However, if your ISP uses either type of PPP, you do not need to separately create an EoA interface. See the PPP help topic for instructions on creating or configuring a PPP interface.

Viewing Your EoA Setup

The EoA table contains a row for each EoA interface currently defined. The table may contain no entries if your ISP does not use the EoA protocol. The following table describes the fields on this page:

  • Interface: The name the software uses to identify the EoA interface.
  • Interface Sec Type: The type of security protections in effect on the interface (public, private, or DMZ):
    • A public interface connects to the Internet (IPoA interfaces are typically public). Packets received on a public interface are subject to the most restrictive set of firewall protections defined in the software.
    • A private interface connects to your LAN, such as the Ethernet interface. Packets received on a private interface are subject to a less restrictive set of protections, because they originate within the network.
    • The term DMZ (de-militarized zone), in Internet networking terms, refers to computers that are available for both public and in-network accesses (such as a company's public Web server). Packets incoming on a DMZ interface -- whether from a LAN or external source -- are subject to a level of protection that is in between those for public and private interfaces.
  • Lower interface: EoA interfaces are defined in software, and then associated with lower-level software and hardware structures (at the lowest level, they are associated with a physical port - the WAN port). This field should reflect an interface name defined in the next lower level of software over which the EoA interface will operate. This will be an ATM VC interface, such as aal5-0, as described in Configuring the ATM VC.
  • Config IP Address and Net Mask: The IP address and network mask you want to assign to the interface. If the interface will be used for bridging with your ISP and you will not be using the device as a router on your LAN, then you do not need to specify IP information. If you enable DHCP for this interface, then the Configured IP address will serve only as a request to the DHCP server. The actual address that is assigned by the ISP may differ if this address is not available.
  • Use DHCP: When enabled, this setting instructs the device to accept IP information assigned dynamically by your ISP's DHCP server. If the interface will be used for bridging with your ISP and you will not be routing data through it, leave this checkbox unselected.
  • Default Route: Indicates whether the ADSL/Ethernet router should use the IP address assigned to this interface, if any, as its default route for your LAN. This can be Enable or Disable. See Configuring IP Routes for an explanation of default routes.
  • Gateway Address: The external IP address that the ADSL/Ethernet router communicates with via the EoA interface to gain access to the Internet. This is typically an ISP server.
  • Status: A green or red ball will display to indicate that the interface is currently up or down, respectively. You cannot manually enable or disable the interface; a down interface may indicate a problem with the DSL connection or the connection to the ISP's access server.
  • Action: Icons you can click on to edit () or delete () the associated EoA interface.

Adding EoA Interfaces

Follow these instructions to add an EoA interface:

  1. If the EoA  page is not already displaying, click the WAN tab, and then click EoA in the task bar.
  2. Click Add to display the EoA Interface - Add page.
  3. Select one of the predefined interface names from the EoA Interface drop down list.
  4. From the Interface Sec Type drop-down list, select the level of IP Firewall to be used on this interface, as defined above. 
  5. In the Lower Interface field, select the lower-level interface name over which this protocol is being configured.

If the interface will be used to provide only a bridged connection to your ISP, skip to step 8.

  1. If you are creating the EoA interface to provide a routed Internet connection, enter the IP address for the interface in the Conf. IP Address field, and enter the network mask. 

    This address serves as the public IP address for your entire LAN and is usually assigned by your ISP.
  2. If your ISP will assign the IP address from their DHCP server, click the Enable radio button in the Use DHCP field.

    When DHCP is enabled, the address you entered in the Conf. IP Address field will be requested from the DHCP server; the server many assign a different address if necessary.
  1. If you are using the EoA interface to provide a routed connection to your ISP and you want the EoA interface to serve as the default route for Internet access for your LAN, ensure that the Default Route: Enable radio button is selected. (If you have more than on WAN interface, note that only one of them can be specified as the default route.) 

    If you are using the interface to provide a bridged connection, then deselect this field.
  2. In the Gateway IP Address field, enter the address of the Internet computer to contact to gain initial access to the Internet.
  3. Click Save Changes. A page displays to confirm your changes.
  4. Click Close to return to the EoA page and view the new interface in the table.
  • If the interface will be used to provide only a routed connection to your ISP, skip to step 16. 
  • If the interface will be used to provide a bridged-only connection or a bridged-and-routed connection to your ISP, then continue with step 12 to enable bridging.
  1. Click the Bridging tab. 
  2. In the interface table, select all interface names on which you want to perform bridging and click Add. To enable bridging with your ISP, select the EoA interface and the LAN interface(s) (eth-0 and/or usb-0). You can enable bridging on an IP-enabled EoA interface; in this case, the same interface will be capable of handling both bridged and routed data packets.
  3. Click the Bridging: Enable/Disable link.
  4. Click the Bridging: Enabled radio button (if not already selected), and then click Save Changes.

NOTE: If want your changes to be permanent, be sure to Write Settings to Flash.